Some vehicles such as automobiles in recent years include a drive assist system mounted thereon that recognizes the dynamically changing situation around the vehicle including pedestrians and traffic lights so as to assist the driver to drive the vehicle or to make decisions. Most of such drive assist systems take an image of a traffic light or a pedestrian with a CCD camera or the like, recognize the condition of the traffic light or pedestrian through image processing of the taken image, and use the recognized results in assisting the drive as mentioned above. However, a pedestrian typically varies numerously in shape depending on the size, orientation, or presence or absence of an object being carried therewith, so that it is difficult to accurately recognize the presence of a pedestrian from the shape obtained based on the image processing. Although traffic lights generally have standardized sizes and colors, they may appear differently depending on the viewing angle, so that it is difficult to accurately recognize presence of a traffic light from the shape obtained based on the image processing.
Patent Document 1 describes a remote sensing technique for recognizing a measurement target using spectral data collected using a spectral sensor. According to Patent Document 1, measurement targets that are hard to recognize in a visible light region only, such as forest, field, or town, are classified and sorted according to characteristics, using multispectral image data including visible and invisible light regions taken by a spectral sensor mounted on an airplane or satellite, so that the measurement targets are recognized based on the data that is classified and sorted according to characteristics.
With the spectral sensor, brightness (light intensity) of each wavelength is observed so that the characteristics specific to a measurement target are known by comparing the brightnesses of various wavelengths, which enables identification of the measurement target. Patent Document 2 describes such a spectral sensor put into practical use as a hyperspectral sensor having wide bandwidth imaging capability and a high resolution power of several nm to several tens nm.
Application of such a spectral sensor in vehicles such as automobiles is considered recently, for recognizing various measurement targets in the vicinity of the vehicle using spectral data taken by the spectral sensor mounted on the vehicle.